Method of tuning alternating-current circuits.



y M. Qsmsy,V I METHOD SOIE' TUNING -ALTEENATING CURRENT CIRCUITS.

' v ABPLQI'NTON FILED JUNI: 6, 191s.l 1,122,027.

-' Patented Deo. 22, 1914.

` A'T AT NVENTUH MENUEL 559x705' By MTNEEIEES' His TTHNEX purine s'inrns rnrngnr crimen..

MENDEL OSNOS, BERLIN, GERMANY, ASSIGNOR TO GENERAL ELECTRIC COMPANY,

A CORPORATION 0F NEW YORK.

METHOD OF TUNING ALTERNATING-CURRENT CIRCUITS.

Specification of Letters Patent.

Patented ne. 22,1914,

Application filed June 6, 1913. Serial No. 772,102.

rent circuits, and particularly of tuning such circuits for currents of high frequency.

, Heretofore alternating current circuits have been tuned by the use of inductance coils of variable sizes and condensers of adjustable capacity. I propose to eliminate, in whole or in part, the inductance coils, and 'in certain instances the -condensers, heretofore employed for tuning, and to secure the proper inductance in the electric circuit by regulating' the magnetic condition of the electrical apparatus included in the circuit.

To this endA my invention consists in mak- .ing the magnetic condition of certain.V apparatus includedjin the alternating current I quantity..

Y 4es circuit adjustable, andin adjusting the mag.

netic condition of this apparatus until. the self induction of the apparatus gives to the circuit a total inductance of the desired yThe lnovel.features which I believe to be patentably,characteristic of rmy invention are *definitelyl indicated in the claims appended-hereto Theprinciple and the mode of operation of my; vention will be understood from the follo Ydiscussion taken in connection with ,1, accompanying drawings, lin whic and 2 aregraphic'illustrations O f the principle (if-operation of myiinvention. ,-"1

Thefcurve V kof Fig. 1 of the drawings illustrates-the no load-voltage curve of an alternator in 'terms of the exciting ampere turnsJ. z The ordinatesof the curve accordingly 4:indicate j volts and the Y-abscissae indicate'exciting ampere turns. Assuming that the exciting, ampere turns are equal to AT,

`we vfind,that the correspondingjno load voltage is, represented .by A. If `the reactive lor inductiveampereA turns of. the normal load current are equal to a, then the normal load voltage is equal to B. This normal load voltage 1s Vobtained by subtracting the ref active ampere turns at normal load from the exciting ampere turns at no load. The self induction of the machine in ohms is, therefore, found by the following equation L Z(A B) where L is the self induction of the machine and Z is the number of turns of winding that is traversed by the reactive current.-

If we'assume the exciting ampereturns toy be reduced until they are equal; to AT, the corresponding no load voltage will be found.v to be A', and the normal. loadvoltage B. The corresponding self induction L of the machine is then found by the following equation =Z(A B) From an examination of Fig. 1, it will be observed that Ly is very Y considerably greater than L, about three timesias great in the case of the -example illustrated. By

the gradual regulation of the exciting am-` pere turns from AT to AT', it is, therefore,

'possible to vary quite gradually the magnitude of the self 'induction of the alternator, and consequently the-total inductance of the electric` circuit, in which the alternator is included. In the example given, the self induction ofthe machine can be varied in the ratio of labout 1 :3, and in general a still greater adjustment can .be obtained.

My 'invention is of special advantage where high frequency alternators of the in; ductor type are included in the electric/circuit. `The no load voltage curve of an alter nator of the inductor type `is quite symlnet-l rical on each side ofthe point of maximum voltage. chine is illustrated in Fig. 2 of the drawings.

vIf AT and AT. are taken on each side of the apex S, or point of vmaximum voltage, ofthe' voltage curve V', then the self inductionof the machine maybe varied quite considerv ably with slight corresponding voltage variation. y

In the application of my invention to `machines with laminated rotors, for example, machines of the type shown vin the.

'German-patent to Guy, No. 143,630, a fur- The voltage curve of such a ma .tid

-, andi greater' .ineness and accuracy of! adjust- :'lnent. l

Under certain conditionsnit may be found undesirable@ vary *the magnetic saturation y conditions: "of the* alternator; orv the 'maximum variation-@permitted may not'be suiiicient to producc-thedesired quantity of inductance in the circuit. In either of these casesu the magnetic saturation condition-fof argftrans'formerincluded in the alternating 'current-f circuit may vbe varied 'with a pre-j cisely similareffect in its 'self `induction as' i .x'hele'inbefgoi'e described 1inl connection'cwith the' alternator.v The saturation condition 'f of theutransformer may 'be :varied by` cutting v (out aproportional number of turns on both :sides'of the transformer, that is, on the primary as QWellas /the secondaryfiyvindlng, whereby the ratio; vof#transformati on -'of the transformer isf'not *affected The trans-- e former beingincluded inthe alternating curlrentcircuitia'change: infits self induction ef- -flects' a'corresponding change in the total inductanc'e.' 'ofl the circuit. =f The v`adj ustment lof rthe #magnetic saturation condition ofthe .itransfcrmer is oftenu 'of' decided advantage 'because the me're changeof 'the magnetic -Ifconrlition 4'oi'if'a *high frequency alternator -1does,tunder' some circumstances,- necessitate la' greatmany 'direct 'current exciting' ampere turns which are not always easy to 'apply,"as -f'or example, "ifi the voltage curve lis avery flatione Y ff'Anlexample of the? embodiment of my invention'ir Earsystem of Wirelesssignaling is -diagrammaticallyillustrated in Fig. 3 Of the accoxnpanying drawings: I- hav'ein this iigu're "shoWn"m`-y invention in vconnection With ahigh vfrequency alternator of the inductor ty'pc'having a stationary? field' -vor exciting Winding 5 connected to a suitable sourceof jt'u'r'e 'Winding- 7 anda rotatable'inductorv 8. `The exciter generator G'has afield 'Winding Qfan'dffa controlling rheostat 10 of the'lusual the-'high 4frequency alternator is connected in the oscillation circuit of a Wireless signaling- 'syst'emf' This 'circuit includescondensers 11 andan 1nductanc'e`12, and 1s" inductively con- A es 'neetedjtovaf grounded antennal13 through a 'exciting current, such 'as 'a direct'lcurrent -f "generator 6, andhavlng'a stationary farma- "construction v.The armature `Windingj ofL transformer 1.5. In accordance with my present invention the saturatlon condltion,

andhence the inductance of the transformer 15,l may be varied adjustinga "correspondf ingly proportional number of primary and secondary turns by means `of an adjusting switch 16. The saturation condition of the alternator may also be varied by means of an adjustable resistance 17 included'in the cir- `cuitf-0f` the eld'winding 5. Adjustment of the resistance 17 'varies the direct current supplied to the field l-Winding `and, asheretofore explained;L 'varies the' saturation" condition i 'of 'the'-alternato1."'"A keV-i I8 is vemployed" for`sendin`g sgnals =Whe`n' therkey *is Irai'sedj theisaturation lcondition of the a1- "ternatc is sofadjusted-bytthe VVamountlof the resistance' Ij'# included in'fthe' field circuit that theel voscillation' circuit'l is properly tuned, and relatively stro'rtgI impulses are radiated 'froml the antenna. i' when' 'thei'lkey 1'81 is' lowered. and the adjustable" resistance 17 'shunted, the saturation"cclditont of ithe' alternator is' solchanged that theloscilla'tion ycircuit is 'no longer'tuned'; and' thef impulses' sent out fr olntlie antenna'- are irelativelyfeeble.4

i l "fI-t willL bWapparent from the foregoing discussion that'I hate-provided a method of 1 tuning anlallternatingtcurrentfcircu'it by adj listing' the magnetic.; condition 'of' electrical apparatus' having magnetic characteristics f included in'thecircuit 'While,1 have described my invention with 'particular reference to the adjustment of the magnetic saturationlcondition'of an' alternator' 'or a transformer"includedfin the circuit,

it'willfbefe'vident that thefinven'tion is not 'limited to'thcse particular'.A kinds of appafr'atu's, butis applicable toi'anyelectrica'l aplparatushaving magnetic characteristics and included fin the electric circuit. Theinductance coils-which'have heretofore been used 'for tuning "purposes 'may be entirely eliminated by vobtaining the proper quantity of inductance i'n the'fcircuit in accordance with myunvention'" In 'some cases, 'however, it'

imay -befoun'd desirable to lreplace the tuning inductance coils only ilrpartzV In certain casesithasalso been ,found'possible' to dispense :with 'the usual tuning condensers `in Whole'or inpartg-'as forv` example, where the capacity o`f`thecirc1'1it` itself and the apparatus included therein is suflicient' and the only requirement'for' resonance is to include "in the'circuit'the proper amount 'of inductance.

if' f My novel method of tuning alternating currentfcircuits' 'may be'carried" out in various other modes tha.n"those mentioned herein. Ido1not, therefore,desire to be limfited :to the* specific' methods f described, but 'aim finf the` appended 'fclai-ms' 'to "cover all methods of tuning *alternating' current circuits-embodying -lthe principle and-Within thefsccpe oflmy nvent1on.f'f"

maracas m What I claim as'new and desire to secure by Letters Patent of the United States, is

l. The -method of tuning an alternating currentcircuit including an alternating current dynamo-electric machine having magnetic characteristics which consists in varying the magnetic saturation condition of said machine until the self induction ofthe machine gives to the circuit a total inductance of the desired quantity. A

2.' The method of tuning an alternating current circuit including an alternator which consists in varying the magnetic-saturation condition of said alternator until the self induction of the alternator gives to the circuit a` total inductance of the' desired quantity.

3. The method of tuning an alternating current circuit including an alternator Which consists in varying the exciting ampere turns of said alternator until the self induction of the alternator gives to the circuit a total inductance of the desired quantity.

4. The method of tuning an alternating current circuit including'an alternator which consists in producing the exciting magnetic field of said alternator by means ofldirect aurrent, and varying the magnitudeif said direct current until the self induction of the alternator gives to the circuit a total Vinductance of the desiredquantity.`

5. The method of .tuning an Valternating current circuit including a high freluency v alternator of the inductor type- Which vconsists in varying the magnetic saturation'condition of said alternator until the self induction of the alternator gives to the circuit a magnetic saturation conditions of the alternator and of the transformer until the self induction of the alternator and of the transformer gives to the circuit a total inductance of the desired quantity.

8. The method of tuning and alternating current circuit including an alternator and a transformer Which consists in varying the magnetic saturation condition of lthe alternator by altering the direct current excitation and varying the magnetic` saturation condition of the transformer until the self induction of the .alternator and the self induction of the transformer give to the cirT cuit a total inductance of the desired quan-A tity. f

In Witness whereof, I have hereunto set my hand thiss26 day o'f May, 1913.

g MENDEL OSNOS. Witnesses: i

RICHARD VENMANN, GUs'rAv WERNER. 

